<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .root {
            width: 2560px;
            height: 1270px;
            background-color: black;
        }

        .header {
            width: 2560px;
            height: 100px;
            background-color: red;
        }
    </style>
</head>

<body>
    <div class="root">
        <div class="header">
            <div class="headerleft">

            </div>
        </div>
    </div>

</body>

</html>